Lithium-Ion Batteries vs. Fuel Cells
Lithium-Ion Batteries and Fuel Cells are two widely used battery technologies in the modern energy sector, playing crucial roles in energy conversion and storage. However, they exhibit significant differences in their operating principles, application areas, and characteristics. Let’s explore the key distinctions between these two battery technologies in the following.
1. Difference in Operating Principles
The operating principle of a fuel cell is similar to that of a lithium-ion battery , both involving the release of electricity when negative electrode materials are oxidized by positive electrode materials.
In the case of a fuel cell, it’s a reaction where hydrogen and oxygen combine to form water, similar to slow combustion. The difference lies in the use of H ions instead of Li ions for the charge and discharge processes, which is why fuel cells can also be referred to as ‘H (hydrogen) ion batteries.’
However, it’s important to note that currently, only non-rechargeable, single-use fuel cells have been commercialized.
2. Comparison of Characteristics Between Lithium-Ion Batteries and Fuel Cells
Safety Hazards of Fuel Cells: The leakage and control of hydrogen gas are the main sources of safety hazards in fuel cell systems, and they belong to the physical aspect.
On the other hand, safety hazards in lithium-ion batteries mainly stem from hard-to-control chain reactions, which belong to the chemical aspect.
Because chain reactions happen extremely quickly, from a controllability standpoint, lithium-ion batteries are more challenging to control than fuel cells.
However, in cases of extreme and violent collisions, the potential harm caused by fuel cells is greater.
Of course, this is only a theoretical consideration, as the rapid escape characteristics of hydrogen gas result in very short leak times.
Moreover, high-pressure hydrogen cylinders are designed to withstand impacts, falls, gunshots, and other unconventional conditions, providing safety assurance.
(2) Low-Temperature Performance
Due to the increased viscosity of the electrolyte and decreased electrical conductivity at low temperatures, the internal resistance of the battery increases sharply, which generally discourages discharge below zero degrees Celsius.
Therefore, lithium-ion batteries require external heating to address low-temperature issues.
Fuel cells have poor low-temperature starting performance, but as they start and generate their own heat, the temperature of the cell stack stabilizes quickly within the normal working temperature range of 80-90°C.
However, how fuel cells achieve low-temperature starting, especially without the use of external auxiliary power, is an important research topic.
Overall, both fuel cells and lithium-ion batteries are more expensive than traditional energy sources.
In particular, the complexity and strict requirements for the source, storage, and safe use of hydrogen have led to high costs for hydrogen fuel cells, making it difficult to gain an advantage in the short term.
Looking at large-scale production data, lithium-ion battery costs will eventually exceed 1000 yuan/kWh（appr USD 143 / kWh）.
The cost of fuel cells is still high at present, and it is expected to approach the current internal combustion engine prices in the long term with the possibility of large-scale implementation.
(4) Charging Duration
The lengthy charging time has always been an enduring pain point for lithium-ion batteries .
In the typical charging mode, a vehicle equipped with a lithium-ion battery takes 3 to 8 hours to fully charge.
In contrast, fuel cells are much more convenient and quick. For example, with hydrogen fuel cells, refueling with hydrogen takes only 3 to 5 minutes to get back to full power.
This may be the biggest pain point for all electric vehicles, especially lithium-ion battery cars.
Traditional lithium-ion batteries are difficult to exceed 500 km in terms of range.
In contrast, fuel cells with higher energy density and lighter weight can achieve even longer ranges.
(6) Temperature Impact
Fuel cell vehicles can maintain the same range as in summer through comprehensive vehicle thermal management, which lithium-ion batteries cannot achieve.
Whether it’s PTC heating or air conditioning, lithium-ion batteries consume electricity.
Fuel cells consume electricity for air conditioning in summer. But in winter, they only use waste heat for passenger compartment insulation and heating. So theoretically, the range in winter should be longer than in summer.
Currently, there are organizations conducting waste heat power generation research based on the Rankine cycle, which, if successful, will further improve the efficiency of fuel cells.
(7) Cost Balance
The cost balance points differ between fuel cell vehicles and pure electric vehicles, with passenger cars being around 500 kilometers and commercial vehicles around 100 kilometers.
Hydrogen fuel cell systems are more suitable for replacing diesel engines,
While lithium-ion battery systems are more suitable for replacing gasoline engines.
Hydrogen Fuel Cells
Quick refueling in 3-5 minutes with direct hydrogen injection
Long charging times, ranging from 3 to 8 hours for a full charge
Degree of Pollution
The primary component of hydrogen fuel cells is hydrogen, which does not pollute the environment at the end of its lifespan
Lithium-ion batteries contain toxic pollutants such as heavy metals like nickel, cobalt, and arsenic, requiring recycling and proper disposal
A range of over 500 kilometers
Typically provides a range of 150-250 kilometers, with only a few products like Tesla offering ranges exceeding 300 kilometers
Charging Station Cost
High costs for hydrogen refueling stations, ranging from 1 to 2 million US dollars
The construction cost for Tesla Supercharger stations is approximately 300,000 yuan
High costs for the catalyst required in the chemical reactions of hydrogen fuel cells, which use rare and expensive metals like platinum, even more costly than gold
Lithium-ion batteries are widely used in smartphones, laptops, and cars, and are cost-effective
In conclusion, fuel cells and lithium-ion batteries are two technologies that may coexist in the future for an extended period.
This is because they complement each other in terms of technical deficiencies, meeting user demands and experiences.
On the other hand, when fuel cells and lithium-ion batteries work together, it can extend the lifespan of fuel cells. Currently, most fuel cell vehicles on the market are equipped with both fuel cells and lithium-ion batteries or nickel-metal hydride batteries.
The presence of lithium-ion or nickel-metal hydride batteries helps maintain a stable power output for fuel cells over the long term, which is beneficial for extending the lifespan of fuel cells.